Safety indicator and control for elevators.



P. T. KENNY.

SAFETY INDICATOR AND CONTROL FOR ELEVATORS. APPLIOATION FILED MAY 26, 1909. RENEWED JAN. 3, 1913.

Patented Mar.4, 1913.

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I M ijy PAUL 'r. KENNY, on NEW YORK, N. Y.

SAFETY INDICATOR AND CONTROL FOR ELEVATORS.

Specification of Letters Patent.

Patented Mar. 4, 1913.

Application filed May 26, 1909, Serial No. 498,509. Renewed January 3, 1913. Serial No. 740,085.

To all whom it may concern:

Be it known that I, PAUL T. KENNY, a citizen of the United States, residing in the borough or" Manhattan, in the city, county, and State of New York, have invented certain new and useful Improvements in Safety Indicators and Controls for Elevators, of which the following is a specifica tion. 0 This invention relates to the control of electric elevators; and, while it isshown in the drawings as applied to the type known as electric traction elevators, it is equally capable of use with other types of electric elevators. In electric elevators it is customary to operate the machinery from a car switch, and it occasionally happens that, when the car is either heavily overloaded, or, conversely, underloaded (when the weights and their supporting cables are in certain parts of the shaft), the machinery has atendency to race, due to the momentum of the car, or of the counterweights, with the result that a stupid operator may cause an accident by failing to throw his car switch to neutral position.

The object of my invent-ion is to" automatically take the control out of the hands of the operator when a dangerous speed is reached.

Further objects are, before taking the control' away from the operator to give him a suitable warning, as a green light in the car;

I when the control is taken away from him to give a further signal, as a red light in the car; when the car slows down of its own accord to automatically extinguish the signal lights and return the control to the operator; and if, after the control is taken awayfrom the operator, the car fails to slow down, to apply a brake to the hoisting mechanism.

The invention resides in the means and devices whereby these ends are attained, all as pointed out in the following description and illustrated in the drawings, together with the numerous equivalent arrangements that may be resorted to.

In the accompanying drawings forming part of the application, Figure 1 is a perspective View, showing hoisting mechanism,

car, and counter-weights, and also diagrams of thecircuits; Fig. 2' is a detail view of the 1 lockfor holding a brake applied to the hoistin mechanism; and Fig. 3 is a detail view 0 a composite brake that may be employed.

In the semi-diagrammatic drawing, the numeral 1 may indicate the car, 2 and 3 the sheaves which, in an electric traction ele-- vator, take the place of an ordinary hoisting drum, and k the motor connected directly to one of the sheaves. 5 are the cables and 6 the counterweights.

The car is controlled by the operator by a switch 7, cooperating with two contacts 8 and 9, as usual. When the switch 7 rests on contact 8, the controlling solenoid 10 is energized; when on contact, 9, the solenoid 11. This arrangement and the solenoids themselves are all as is customary in electric elevators, so that particular illustration and each solenoid, one of the three sets of con tacts, we will. say, pertains to the fieldof the motor 1, another to the armature, and. a third to the brake. The only difference between the two solenoids, as is well understood, is that with one the current flows in one direction through the armature, while with the other it flows in the reverse direction. energized the car travels in one direction, say down, and when the solenoid 11 is ener' gized, it travels in the reverse direction, or up. When the switch 7 is in mid-position the motor is dead and the brake is on, so that the car is stationary. It will be understood that all the foregoing, pey .96, is old.

14 is a governor, driven'by the hoisting mechanism, and conveniently mounted on the shaft of the sheave 3. 15 is a switch, adapted to cooperate with three contacts, 16 and 17 and 18. The contact portion of the switch 15 may be broad enough to bridge two of the stationary contacts; but-a desirable construction is one in'which the switch has a contact finger l9 pivoted thereto, so-

Consequently, when the solenoid 10 is v Normally the switch 15 engages only with contact 16. When safe speed islexceeded,

' the switch 15 is shifted by the governor 14 to the right, engaging contact 17, but still being in engagement with contact 16, as described. When a really dangerous speed is reached, the switch is thrown farther to the right, engaging contact 18, and moving suddenly away from contact 16. The results of these movements will become apparent by following out the diagrammatic and illustrative form of wiring shown. Assuming the car switch 7 is on one or other of its contacts, and that the switch 15 is in engagement only with contact 16, current flows from one side of the generator or source 21, throughone of the solenoids, energizing the same, through the wire 22, contact 16, switch 15, wire 23, and to the other side of the generator. If the switch 15 be bridging the contacts 16 and 17, the course of the current is the same, except that a portion thereof passes through wire 24, lamp 25 (say a green. lamp) in the car, wire 26, and contact 17.

The result is that, whilethe operator still I has control of the car, a signal is given warning him that danger speed is being reached. But when the switch 15 no longer, engages with contact 16, and either engages contact 18 or bridges contact 17 and 18, then the circuit through the solenoid is broken automatically, and, current passes through wire 24, lamp 27 (say a red lamp), wire 28 and contact 18.

The solenoid being denergized and its core down, the motor circuits are broken andthe motor brake applied. Hence, the car slows down, and thegovernor 14 resumes its normalposition, permitting the switch 15 to be returned to normal position, in engagement with contact 16fonly, under the im.-

pulse of any suitable returning means, as a spring 29. In this way, the car switch 7 still being on its'contact; the current is again completed through the solenoid, and the car proceeds slowly.- v If for any reason the foregoing operations 'shouldfai-l to slow the car, and on the contrary its speed should continue .toincrease, I propose .to-cause the further abnormal movement of the governor 14 to apply a mechanical brake directly to the hoisting mechanism. Such a brake is represented by the numeral 30, being adapted to coiiperate with one of the sheaves. Preferably this is formed of two parts 31 and 32, thejpart 31 being adapted to engage with the periphery of the sheave, and the part 32 being adapted to engage with the. cables passing around the sheave. Between thetwo parts are interposed springs 33; and the part 32 is connected with the governor. Suitable connections may comprise abell-crank lever 34, on which the part 32 is mounted, a link 35, and a yoke 36 connected with the sliding sleeve closes a local circuit containin of the governor; Of course any other mode of connection may be resorted to. o The re sult to be attained is that the brake engages first with the sheave; and then, as a last resource, the part 32 is brought into engagement with the cables themselves, compressing the springs 33 for this purpose.

' While the brake is connected with the governor so that, under ordinary condition, the slowing down of the governor due to the braking effect will automatically release the brake, I consider it a highly desirable fea ture of my inventionthat I provide a lock, which becomes operative automatically at a very excessive speed to lock the brake in appliedposition. This is of great importance in event of breaking of cables, in which event the hoisting mechanism would move at a looking relation by reason of a. locking shoulder 44, which cooperates with the projection 42 tohold thebrake applied. As stated, the

parts are so proportioned, preferably, that this occurs when the brake has been set hard enough to apply the brake part 32 against the cables. A weight 37 may be employed to insure the action of the arm 38.

A further development of the invention 'comprehends a signal which is sounded or displayed, or'both, exterior to the car, when the brake is locked, so that the janitor or other attendant of the building. will be' warned that the hoisting mechanism is locked and cannot be released from within the car. Such a signal might'be located in the basement or in the main hall of the buildin Obviously the signal -may be various y arranged and constructed. In thedrawing it is diagrammatically indicated. When the switch 15 rests on con- .tact 18, a solenoid 45 is energized, tilting a pivoted latch lever 46, thus permitting the fall of a visual shutter 47, which, in turn, I a bell or buzzer .48. -B the' continued isplay and sounding of t is signal the attendant will know that the hoistin mechanism is locked.

The lock may be re eased by simply raising the arm 38, or the arm may have pivoted thereto a lifting device 40, held in normal position by a spring 41, and adapted to be pressed down upon the stud 42 by a wrench gripping the nut 43. v.

If desired a further braking action may be exerted against the sides of the sheave. Many forms of apparatus may be used for this purpose; that shown in Fig. 3 is intended to be merely illustrative. Brake shoes 51"are carried by arms pivotally supported at their upper ends to frame members 52 and adapted to be pressed against the sides of the sheave by rollers 53 on the brake part 32 rolling up inclines on the tails of the arms 50.

While I have shown the several brake devices as cooperating withjthe sheave 3 it will be obvious that they could as well engage with the sheave 2.

If desired, an adjustableengagement device 39 may be interposed between the governor 14 and the switch 15.

\Vhat I claim as new is:

1. A safety electric elevator control system comprising control circuits and a car switch, two car signals and circuits, and an auxiliary automatic switch adapted as the speed increases first to complete one signal circuit and then to break the control circuits and complete the other signal circuit.

2. A safety electric elevator control system, comprising an electric motor, raising and lowering mechanism driven thereby, a mechanical brake adapted to be applied to the raising and lowering mechanism, two controlling solenoids adapted when energized to cause the motor to run in opposite directions, a car switch adapted to energize either of said solenoids, and a speed governor adapted to deenergize the energized solenoid whenever a predetermined speed is reached, said speed governor being connected also with said mechanical brake to apply the same when a dangerous speed is reached, said switch and brake being adapted to return automatically to normal positions when the speed decreases.

3. A safety electric elevator control system, comprising an electric motor, raising and lowering mechanism driven thereby, a

. mechanical brake adapted to be applied to the raising and lowering mechanism, two, controlling solenoids adapted when energized to cause the motor to run in opposite directions, a car switch adapted to energize either of said solenoids, an auxiliary switch adapted to dee'nergize the energized solenoid, a speed governor adapted to operate said switch when a predetermined speed is reached, connections between said governor and said brake whereby the latter is. applied at a predetermined speed, and automatic means for locking said switch open and said brake applied.

4. A safety electric elevator control system comprising raising and lowering mechanism, control circuits, and a car switch, a governor, an auxiliary automatic switch adapted to be operated by said governor as the speed increases to break said control circuits, a mechanical brake"associated with the raising and lowering mechanism also adapted to be actuated by said governor'as the speed increases and to be released as the hold said brake applied to the raising and lowering mechanism.

5. A safety electric elevator control system comprising raising and lowering mechanism, control circuits and a car switch, a governor, an auxiliary automatic switch adapted to be operated by said governor as the speed increases to break said control circuits, a mechanical brake associated with the raising and lowering mechanism also adapted to be actuated by said governor as the speed increases and to be released as the speed thereof diminishes again, an automatic lock adapted to become operative at a very excessive speed of the governor to hold said brake applied to the raising and lowering mechanism, and a signal exterior of the car adapted to be actuated when said brake I is locked.

PAUL T. KENNY. 

